Digital Subscriber Line (DSL) technology, often referred to as “broadband”, is a family of services that provide digital data transmission over the metallic twisted copper pairs that form part of a local telephone network. DSL is commonly used to provide a customer's home with a network connection, typically to the Internet via an ISP.
DSL broadband lines are prone to faults. These include slow line speeds or line drop outs. Some of these faults are easily identified and rectified, such as missing micro-filters in the customer's home. Others are more complex, such as faults resulting from external RF interference or faulty cabling. Diagnostic methods have been developed to help identify the cause of such faults and to propose solutions.
Some methods look at the line statistics that are measured by the modem or at the exchange, such as the signal to noise ratio or line attenuation, and try and match them to known potential faults. More persistent problems or difficult to identify problems require more detailed investigation, sometimes with an engineer. However, even engineers with various testing tools at their disposal often struggle to identify some faults. Moreover, there is often an issue of whether there is an actual fault with the line or whether the symptoms observed are typical for similar lines.